* ARM System MMU Architecture Implementation

ARM SoCs may contain an implementation of the ARM System Memory
Management Unit Architecture, which can be used to provide 1 or 2 stages
of address translation to bus masters external to the CPU.

The SMMU may also raise interrupts in response to various fault
conditions.

** System MMU required properties:

- compatible    : Should be one of:

                        "arm,smmu-v1"
                        "arm,smmu-v2"
                        "arm,mmu-400"
                        "arm,mmu-401"
                        "arm,mmu-500"
                        "cavium,smmu-v2"
                        "qcom,qsmmu-v500"
                        "qcom,smmu-v2"

                  depending on the particular implementation and/or the
                  version of the architecture implemented.

- reg           : Base address and size of the SMMU.

- reg-names	: For the "qcom,qsmmu-v500" device "tcu-base" is expected.

- #global-interrupts : The number of global interrupts exposed by the
                       device.

- interrupts    : Interrupt list, with the first #global-irqs entries
                  corresponding to the global interrupts and any
                  following entries corresponding to context interrupts,
                  specified in order of their indexing by the SMMU.

                  For SMMUv2 implementations, there must be exactly one
                  interrupt per context bank. In the case of a single,
                  combined interrupt, it must be listed multiple times.

- #iommu-cells  : See Documentation/devicetree/bindings/iommu/iommu.txt
                  for details. With a value of 1, each IOMMU specifier
                  represents a distinct stream ID emitted by that device
                  into the relevant SMMU.

                  SMMUs with stream matching support and complex masters
                  may use a value of 2, where the second cell of the
                  IOMMU specifier represents an SMR mask to combine with
                  the ID in the first cell.  Care must be taken to ensure
                  the set of matched IDs does not result in conflicts.

** System MMU optional properties:

- dma-coherent  : Present if page table walks made by the SMMU are
                  cache coherent with the CPU.

                  NOTE: this only applies to the SMMU itself, not
                  masters connected upstream of the SMMU.

- calxeda,smmu-secure-config-access : Enable proper handling of buggy
                  implementations that always use secure access to
                  SMMU configuration registers. In this case non-secure
                  aliases of secure registers have to be used during
                  SMMU configuration.

- stream-match-mask : For SMMUs supporting stream matching and using
                  #iommu-cells = <1>, specifies a mask of bits to ignore
		  when matching stream IDs (e.g. this may be programmed
		  into the SMRn.MASK field of every stream match register
		  used). For cases where it is desirable to ignore some
                  portion of every Stream ID (e.g. for certain MMU-500
                  configurations given globally unique input IDs). This
                  property is not valid for SMMUs using stream indexing,
                  or using stream matching with #iommu-cells = <2>, and
                  may be ignored if present in such cases.
- attach-impl-defs : global registers to program at device attach
                  time. This should be a list of 2-tuples of the format:
                  <offset reg_value>.

- qcom,fatal-asf : Enable BUG_ON for address size faults.  Some hardware
                  requires special fixups to recover from address size
                  faults.  Rather than applying the fixups just BUG since
                  address size faults are due to a fundamental programming
                  error from which we don't care about recovering anyways.

- qcom,tz-device-id : A string indicating the device ID for this SMMU known
		  to TZ.  See msm_tz_smmu.c for a full list of mappings.

- qcom,skip-init : Disable resetting configuration for all context banks
                  during device reset.  This is useful for targets where
                  some context banks are dedicated to other execution
                  environments outside of Linux and those other EEs are
                  programming their own stream match tables, SCTLR, etc.
                  Without setting this option we will trample on their
                  configuration.

- qcom,dynamic  : Allow dynamic domains to be attached. This is only
		  useful if the upstream hardware is capable of switching
		  between multiple domains within a single context bank.

- qcom,use-3-lvl-tables:
		  Some hardware configurations may not be optimized for using
		  a four level page table configuration. Set to use a three
		  level page table instead.

- qcom,no-asid-retention:
		  Some hardware may lose internal state for asid after
		  retention. No cache invalidation operations involving asid
		  may be used.

- qcom,actlr:
		  An array of <sid mask actlr-setting>.
		  Any sid X for which X&~mask==sid will be programmed with the
		  given actlr-setting.

- qcom,enable-static-cb : Enables option to use pre-defined static context bank
		  allocation programmed by TZ. Global register including SMR and
		  S2CR registers are configured by TZ before kernel comes up and
		  this programming is not altered throughout the life of system.
		  We would be reading through these registers at run time to
		  identify CB allocated for a particular sid. SID masking isn't
		  supported as we are directly comparing client SID with ID bits
		  of SMR registers.

-qcom,disable-atos:
		  Some hardware may not have full support for atos debugging
		  in tandem with other features like power collapse.

-qcom,opt-out-tbu-halting:
		  Allow certain TBUs to opt-out from being halted for the
		  ATOS operation to proceed. Halting certain TBUs would cause
		  considerable impact to the system such as deadlocks on demand.
		  Such TBUs can be opted out to be halted from software.

- qcom,deferred-regulator-disable-delay : The time delay for deferred regulator
                  disable in ms. In case of unmap call, regulator is
                  enabled/disabled. This may introduce additional delay. For
                  clients who do not detach, it's not possible to keep regulator
                  vote while smmu is attached. Type is <u32>.

- qcom,no-dynamic-asid:
		  Clients that uses the dynamic domains will have an unique asid
		  per each domain and all domains can share the same context bank.
		  When ASID based invalidation is used, on some hardware revisions,
		  as a result of multiple ASID's associated with the same context
		  bank, TLB entries are not invalidated properly. On such systems,
		  we can choose to have a single ASID associated with all domains
		  for a context bank.

- qcom,testbus-version:
		  Testbus implementation is different in some hardware for eg some doesn't
		  have a separate register for programming tbu testbuses so, they share the
		  same register to program both tcu and tbu testbuses. on such hardware this
		  option can be used to specify the testbus version to support testbus interface.
		  Type is <u32>.

- qcom,iommu-geometry:
          Allow clients to extend the available IOVA space by setting the
          DOMAIN_ATTR_GEOMETRY domain attribute. The new IOVA space created
          will be a superset of the IOVA range which was created through the
          create mapping call. The DOMAIN_ATTR_GEOMETRY domain attribute can
          only be set before attaching.

- clocks        : List of clocks to be used during SMMU register access. See
                  Documentation/devicetree/bindings/clock/clock-bindings.txt
                  for information about the format. For each clock specified
                  here, there must be a corresponding entry in clock-names
                  (see below).

- clock-names   : List of clock names corresponding to the clocks specified in
                  the "clocks" property (above). See
                  Documentation/devicetree/bindings/clock/clock-bindings.txt
                  for more info.

- (%s)-supply   : Phandle of the regulator that should be powered on during
                  SMMU register access. (%s) is a string from the
		  qcom,regulator-names property.

- qcom,regulator-names :
		  List of strings to use with the (%s)-supply property.

- qcom,msm-bus,name
- qcom,msm-bus,num-cases
- qcom,msm-bus,num-paths
- qcom,msm-bus,vectors-KBps
		: Refer to devicetree/bindings/arm/msm/msm_bus.txt

** Deprecated properties:

- mmu-masters (deprecated in favour of the generic "iommus" binding) :
                  A list of phandles to device nodes representing bus
                  masters for which the SMMU can provide a translation
                  and their corresponding Stream IDs. Each device node
                  linked from this list must have a "#stream-id-cells"
                  property, indicating the number of Stream ID
                  arguments associated with its phandle.

** Additional properties for Iommu Clients:
- qcom,iommu-dma:
		Optional, String.
		Can be one of "bypass", "fastmap", "atomic", "disabled".
--- "default":
		Standard iommu translation behavior.
		The iommu framework will automatically create a domain for the client.
		iommu and DMA apis may not be called in atomic context.
--- "bypass":
		DMA APIs will use 1-to-1 translation between dma_addr and phys_addr.
		Allows using iommu and DMA apis in atomic context.
--- "fastmap":
		DMA APIs will run faster, but use several orders of magnitude more memory.
		Also allows using iommu and DMA apis in atomic context.
--- "atomic":
		Allows using iommu and DMA apis in atomic context.
--- "disabled":
		The iommu client is responsible for allocating an iommu domain, as
		well as calling iommu_map to create the desired mappings.

- qcom,iommu-faults:
		Optional, List of Strings.
		The SCTLR register setting which affect iommu faults handling.
		Any combination of the below strings may be used. Mutliple
		values are accepted.
--- "default":
		Any faults are treated as fatal errors.
--- "no-CFRE":
		Iommu faults do not return an abort to the client hardware.
--- "non-fatal":
		Iommu faults do not trigger a kernel panic.
--- "stall-disable":
		Iommu faults do not stall the client while the fault
		interrupt is being handled.
--- "HUPCF":
		Iommu may process other transactions while a fault is
		in the process of being handled.
- qcom,iommu-vmid:
		Optional, Int.
		An identifier indicating the security state of the client.

- qcom,iommu-pagetable:
		Optional, String.
		Enables coherency for the IOMMU device, but not for the Client.
--- "default":
		Pagetables are not coherent nor cached in the system cache..
--- "coherent"
		Pagetables are io-coherent.
--- "LLC"
		Pagetables may be saved in the system cache.
--- "LLC_NWA"
		Pagetables may be saved in the system cache is used, and
		 write-allocate hint is disabled.

- qcom,iommu-earlymap:
		Optional, Bool.
		Support creating mappings in the page-table before Stage 1 translation is
		enabled.

- qcom,iommu-dma-addr-pool:
		Optional, tuple of <address size>.
		Defaults to <0, SZ_4G> if not present.
		Indicates the range of addresses that the dma layer will use.

** Examples:

        /* SMMU with stream matching or stream indexing */
        smmu1: iommu {
                compatible = "arm,smmu-v1";
                reg = <0xba5e0000 0x10000>;
                #global-interrupts = <2>;
                interrupts = <0 32 4>,
                             <0 33 4>,
                             <0 34 4>, /* This is the first context interrupt */
                             <0 35 4>,
                             <0 36 4>,
                             <0 37 4>;
                #iommu-cells = <1>;
        };

        /* device with two stream IDs, 0 and 7 */
        master1 {
                iommus = <&smmu1 0>,
                         <&smmu1 7>;
        };


        /* SMMU with stream matching */
        smmu2: iommu {
                ...
                #iommu-cells = <2>;
        };

        /* device with stream IDs 0 and 7 */
        master2 {
                iommus = <&smmu2 0 0>,
                         <&smmu2 7 0>;
        };

        /* device with stream IDs 1, 17, 33 and 49 */
        master3 {
                iommus = <&smmu2 1 0x30>;
        };


* Qualcomm MMU-500 TBU Device

The qcom,qsmmu-v500 device implements a number of register regions containing
debug functionality. Each register region maps to a separate tbu from the
arm mmu-500 implementation.

** TBU required properties:

- compatible    : Should be one of:
                        "qcom,qsmmuv500-tbu"

- reg           : Base address and size.

- reg-names	: "base" and "status-reg" are expected
		"base" is the main TBU register region.
		"status-reg" indicates whether hw can process a new request.

-qcom,stream-id-range:
		Pair of values describing the smallest supported stream-id
		and the size of the entire set.

Example:
smmu {
	compatible = "qcom,qsmmu-v500";
	tbu@0x1000 {
		compatible = "qcom,qsmmuv500-tbu";
		regs = <0x1000 0x1000>,
			<0x2000 0x8>;
		reg-names = "base",
			"status-reg";
		qcom,stream-id-range = <0x800 0x400>;
	};
};
